Omicron is now the dominant strain of COVID-19 around the world and boosters targeting this variant are getting closer to being released.
So if you are eligible for a fourth booster shot, should you wait until these new Omicron-specific boosters have been approved or get in line now for what's on offer?
Here's what the experts say.
How well do the current vaccines protect against Omicron?
The vaccines available in Australia as boosters all greatly reduce your chances of severe illness, hospitalisation or death if you get any variant.
However, against Omicron, they are less effective at stopping you from getting infected in the first place.
Over time, the COVID-19 virus has mutated and evolved and the Omicron variant currently causing caseloads to surge has a few quirks the "original" variant does not.
Most vaccines on the market were created targeting the original strain of SARS-CoV-2 and helped reduce recipients' chances of getting infected, even against some later variants.
The mutations Omicron has, however, make it more likely to evade the protection you have from existing vaccines.
"These new sub-variants have changed enough now that the original vaccines, while still very important and really important for people to be up to date with at the moment, perhaps don't provide quite enough protection as we would like to see," Paul Griffin, an infectious diseases physician and clinical microbiologist, says.
But current vaccines still play an important role in protecting against COVID-19, Jeremy Kamil, an associate professor of microbiology and immunology at Louisiana State University, says.
They help protect against severe disease, even from Omicron, and have prevented millions of deaths and severe illnesses around the world.
"I'm afraid that so many people in the public just come away with this impression that the vaccines are useless now, which couldn't be farther from the truth," Dr Kamil told the ABC Daily news podcast.
"The vaccines are incredibly successful at saving people's lives, and there's many facets of immunity that they provide which remain effective."
What are the main benefits of an Omicron-specific vaccine?
The idea behind updated booster shots is that they will improve your immune system's ability to recognise Omicron and help reduce your chances of getting really sick.
"We've gotten to a point now where Omicron has taken over and really is the main virus that's circulating in almost all countries, if not all countries," says Jennifer Juno, an immunologist from the Peter Doherty Institute for Infection and Immunity.
"And so we want to update our immune system's ability to be able to recognise the characteristics of the spike protein that are unique to Omicron."
The big picture is that variant-specific booster shots should help reduce transmission.
Daniel Layton, an immunologist with the CSIRO, says this is one of the reasons why it is important to update the vaccines to target Omicron.
"We're seeing that people are getting infected even as little as eight weeks after their prior infection," he said.
"By updating the vaccine to currently circulating strains, we can potentially reduce that reinfection rate and reduce the total disease burden on people."
What Omicron-specific vaccines are in development?
The main Omicron boosters we're likely to see in Australia are from Pfizer and Moderna.
Both companies are developing "bivalent" or combination vaccines, which means they will contain protection against Omicron as well as the original strain.
Trials comparing these new vaccine candidates with existing ones are in the late stages, but early results released by the companies look promising.
The new options boost neutralising antibodies against Omicron and both have been shown to be as safe as similar vaccines already on the market.
Pfizer and Moderna's boosters will target a specific sub-variant of Omicron known as BA.1, but their trials show they should also protect against other types of Omicron.
There are a number of other COVID-19 vaccines being trialled in Australia, but they are much further away from being rolled out.
When will they be available in Australia?
It is hard to give an exact date, but it could be before the end of this year.
Dr Griffin says it is not clear which company's vaccine will get approved first.
Both Moderna and Pfizer say they will work closely with the federal government to supply vaccines as quickly as possible once they are approved.
The Therapeutic Goods Administration (TGA) is currently reviewing Moderna's submission to supply its combination vaccine in Australia.
"If approved, the company will be able to supply this new Omicron-containing bivalent booster vaccine within weeks [of the approval], putting Australia amongst the first countries in the world to have access to this new COVID-19 vaccine," a Moderna spokesperson said.
Pfizer has already received "provisional determination" for its bivalent vaccine, the first hurdle in getting a vaccine approved for wide use.
The company already has an agreement to provide Australia with 85 million additional doses up to 2023, and that includes newer versions of the vaccine.
The ABC asked the federal government if any Omicron-specific boosters had been ordered yet.
"Registration and supply in Australia will only commence should the vaccine be approved as safe and effective by the TGA," a health department spokesperson said.
"The department is working closely with manufacturers to ensure access to the most-updated vaccines."
Should I get a fourth dose now or wait for Omicron vaccines?
Most experts say getting boosted with what is available as soon as you can is your best protection against getting sick from COVID-19.
"My advice would be for everybody to get up to date with their vaccines," Dr Griffin says.
"What's clear is, while this additional dose won't provide the same magnitude of benefit that we saw previous boosters do, it's still going to be very significant."
If you are 30, you are now eligible for a fourth dose, and ATAGI strongly recommends getting one if you are over 50.
For the under-50 age group, it comes down to personal preference, Dr Layton says.
"The reason why that hasn't been a strong recommendation is that currently in that age demographic, we don't see a lot of hospitalisation and death," he said.
"But certainly if people want to protect themselves during this cold, flu and COVID season, and make sure they've got the highest level of antibodies possible, it certainly would be good timing to do it now."
And getting a fourth dose now does not mean you will not be able to get an Omicron booster later, he said.
Dr Griffin says hospitals are already struggling with the wave of illness and it is likely to increase.
"And so we need as many people as maximally protected right now as possible," he says.
For any specific medical concerns or advice about your situation, it is always best to speak to your GP.
Is there a risk the vaccines will get outdated?
All viruses evolve and mutate over time — and this is already affecting COVID-19 vaccine development.
The virus is still evolving quickly, with experts admitting it is challenging for scientists to keep up.
But new technology and innovation is helping to close the gap.
"There are a lot of efforts underway to develop a pan-coronavirus vaccine … where that race will no longer be an issue and we'll get protection against whatever variant arises," Dr Griffin says.
"So it is a challenge, but we're going to get better tools."
